Integrated Photonics Module and Devices Using Integrated Photonics Modules

ABSTRACT

An integrated photonics module includes at least one light source and a MEMS scanner coupled to and held in alignment by an optical frame configured for mounting to a host system. According to some embodiments, the integrated photonics module may include a plurality of light sources and a beam combiner coupled to the optical frame. According to some embodiments, the integrated photonics module includes a selective fold mirror configured to direct at least a portion of emitted light toward the MEMS scanner in a normal direction and pass scanned light through to a field of view. The selective fold mirror may use beam polarization to select beam passing and reflection. The integrated photonics module may include a beam rotator such as a quarter-wave plate to convert the polarization of the emitted light to a different polarization adapted for passage through the fold mirror. The integrated photonics module may include one or more light detectors.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from and incorporates by referenceherein U.S. Provisional Patent Application Ser. No. 60/791,074, filedApr. 11, 2006.

BACKGROUND

Video displays are used in a wide variety of applications, includingportable and fixed-location applications. In at least some applications,and particularly in some portable applications, viewable screen size hasheretofore been limited by the physical extent of product packaging.

OVERVIEW

An integrated photonics module provides a compact swept-beam displaythat may be integrated into a range of systems. According to someembodiments, the compact swept-beam display may be configured to projectan image having a physical extent larger than the physical extent of asystem, product, or package housing the integrated photonics module.

According to some embodiments, an integrated photonics module includesone or a plurality of light sources such as lasers, beam shaping optics,combiner optics, a MEMS scanner, and one or more mechanical componentssuch as an optical frame to facilitate mounting and maintain opticalalignment. According to some embodiments, the integrated photonicsmodule may include some or all of MEMS drive electronics, light sourcedrive electronics, sensors, and video electronics. According to variousembodiments, the MEMS drive electronics may include a MEMS controller,D/A and/or A/D converter(s), and a MEMS drive amplifier(s). Videocontroller electronics may include a light source controller, D/Aconverter(s), and light source drive amplifier(s). According to otherembodiments, an output of an integrated photonics module may substitutea different interface for the beam scanner such as a fiber couplerconfigured to deliver light to a remote scanner.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an integrated photonics module according toan embodiment.

FIG. 2 is a perspective view of at least a portion of an integratedphotonics module according to an embodiment.

FIG. 3 is another perspective view of at least a portion of anintegrated photonics module according to an embodiment.

FIG. 4 is another perspective view of at least a portion of anintegrated photonics module according to an embodiment.

FIG. 5 is another perspective view of at least a portion of anintegrated photonics module including dimensions according to anembodiment.

FIG. 6 is a cut-away view of at least a portion of the integratedphotonics module of FIGS. 2-5 according to an embodiment.

FIG. 7 is another cut-away view of at least a portion of the integratedphotonics module of FIGS. 2-5 according to an embodiment.

FIG. 8 is another cut-away view of at least a portion of the integratedphotonics module of FIGS. 2-5 according to an embodiment.

FIG. 9 is a view of some of the principal optical components of theintegrated photonics module of FIGS. 2-8 according to an embodiment.

FIG. 10 is a view of an optical frame for the integrated photonicsmodule of FIGS. 2-8 according to an embodiment.

FIG. 11 is a perspective view of at least a portion of an integratedphotonics module including a mechanically-coupled circuit boardaccording to an embodiment.

FIG. 12 is a perspective view of a MEMS scanner that may be used in theintegrated photonics module of FIGS. 2-8 according to an embodiment.

FIG. 13 is a diagram illustrating exemplary beam shapes and beam shapingoptics for three applications for integrated photonics modules accordingto embodiments.

FIG. 14 is a diagram illustrating discrete and integrated variants ofbeam shaping optics for an integrated photonics module according toembodiments.

FIG. 15 is a diagram illustrating of at least a portion of an integratedphotonics module for a portable scanned beam projector according to anembodiment.

FIG. 16 is a diagram illustrating an adaptation of at least a portion ofthe integrated photonics module of FIG. 15 to a scanned beam heads-updisplay application according to an embodiment.

FIG. 17 is a diagram illustrating the integration of lens elements ofFIG. 16 into an integrated lens according to an embodiment.

FIG. 18 is a perspective view of at least a portion of an integratedphotonics module showing light transmission paths and the placement ofoptional adaptor optics according to an embodiment.

FIG. 19 is a diagram illustrating the relationship of the light sourcesand the beam combiner of at least a portion of an integrated photonicsmodule according to an embodiment.

FIG. 20 is a diagram illustrating light transmission in at least aportion of an integrated photonics module according to an embodiment.

FIG. 21 is a diagram illustrating light transmission in at least aportion of an integrated photonics module according to anotherembodiment.

FIG. 22 is a diagram illustrating light transmission in at least aportion of an integrated photonics module according to anotherembodiment.

FIG. 23 is a diagram illustrating light transmission in at least aportion of an integrated photonics module according to anotherembodiment.

FIG. 24 is a diagram illustrating light transmission in at least aportion of an integrated photonics module according to anotherembodiment.

FIG. 25A is a diagram illustrating light transmission in at least aportion of an integrated photonics module according to anotherembodiment.

FIG. 25B is a diagram illustrating at least a portion of an integratedphotonics module including non-imaging detectors according to anembodiment.

FIG. 25C is a diagram illustrating at least a portion of an integratedphotonics module with a focal plane detector array according to anembodiment.

FIG. 25D is a diagram illustrating at least a portion of an integratedphotonics module wherein the scanner is aligned to receive a modulatedcomposite beam through the selective mirror according to an embodiment.

FIG. 25E is a diagram illustrating light transmission in at least aportion of an integrated photonics module according to an embodimentwherein the beam scanner is in a plane other than normal to a nominalimage projection direction.

FIG. 26 is a diagram illustrating light transmission in at least aportion of an integrated photonics module according to anotherembodiment wherein one light source is aligned axially with the beamcombiner.

FIG. 27 is a block diagram of a scanner controller comprising at least aportion of an integrated photonics module according to an embodiment.

FIG. 28 is a block diagram of a display controller including lightsource and scanner controller comprising at least a portion of anintegrated photonics module according to an embodiment.

FIG. 29 is a diagram illustrating the use of an integrated photonicsmodule integrated into a mobile electronic device according to anembodiment.

FIG. 30 is a diagram illustrating the use of an integrated photonicsmodule in a heads-up display application according to an embodiment.

FIG. 31 is a perspective view of a portable scanned beam projectiondisplay using an integrated photonics module according to an embodiment.

DETAILED DESCRIPTION

FIG. 1 is a block diagram of an electronic device 101 including anintegrated photonics module 102 for displaying images such as videoimages according to an embodiment. According to the illustrativeembodiment, the integrated photonics module 102 may include interfacesto system resources 104. Video controller electronics 106, which may beembodied as an integrated video application-specific integrated circuit(ASIC) including a system controller and software 108, receives an inputvideo signal. The video controller electronics 106 may at leasttemporarily buffer received video images in video memory 110, which mayinclude frame buffer memory and on-screen display menus. When it is timeto display a new video frame, the video controller electronics 106 readsthe cached video frame from the video memory 110 and sequentially drivesone or more light source drivers 112 to a sequence of brightness valuescorresponding to pixel values in the input video signal. The lightsource drivers 112 drive one or more light sources 116, which may beincluded in an integrated optical engine portion 114 of the integratedphotonics module 102, according to an embodiment. The light sources 116create one or more modulated beams of light that may be shaped andcombined by the combiner and beam shaping optics 118 into a modulatedcomposite beam of light 119. The light sources 116 may, for example,comprise red, green, and blue modulated lasers. According to someembodiments, the modulated composite beam of light 119 may be directedtoward a scanner 120, which may for example be a MEMS scanner, operableto scan the modulated composite beam over a field of view (FOV) tocreate an image.

While the video controller electronics 106 drives the light sourcedrivers 112, it simultaneously drives a scanner controller 122, whichmay optionally be embodied as a scanner drive ASIC that may, accordingto some embodiments, also contain a scanner controller and software 124.The scanner controller 122 is operable to drive the scanner 120 tosequentially scan the emitted light across the FOV as a modulatedscanned beam of light 125 in a periodic scan pattern.

The scanner 120 deflects the modulated beam of light across the FOV toproduce a scanned beam of light 125. The scanned beam of light 125 mayoptionally be conditioned and/or relayed by final optics 126 to producea video image 128.

Taken together, the light sources 116, the combiner and beam shapingoptics 118, and the scanner 120, along with mechanical mountingstructures, actuators, etc., may comprise an integrated optical engine112; which may in turn comprise an integrated photonics module.Instantaneous positions of the scanned beam of light 125 sequentiallyilluminate spots in the FOV, the FOV comprising a display surface, exitpupil expander (EPE), or projection screen. To display an image,substantially all the spots in the FOV are sequentially illuminated,nominally with an amount of power proportional to the brightness of aninput video image pixel corresponding to each spot.

While the beam illuminates the spots, a portion of the illuminatinglight beam is reflected or scattered as scattered energy. A portion ofthe scattered light energy may travel to one or more viewers 130.Persistence of vision in the viewer's eye and mind integrates thesequence of illuminated spots in the FOV into a recognizable video image128 that may comprise static and/or moving images.

According to some embodiments, light detectors (not shown) may also bealigned to receive a portion of the scattered light energy from the FOV.A variety of processing may be applied to the received scattered lightenergy to provide functionality. Some embodiments of the functionalityof detectors that may be included as a portion of an integratedphotonics module. Such detectors may be aligned to receive de-scannedenergy off the scanner via a retro-collective or confocal arrangement,or may be aligned to receive light directly or through relay optics fromthe FOV via a staring detection arrangement.

The light sources 116 may include multiple emitters such as, forinstance, light emitting diodes (LEDs), lasers, thermal sources, arcsources, fluorescent sources, gas discharge sources, or other types ofemitters. According to one embodiment, a light source 116 comprises ared laser diode having a wavelength of approximately 635 to 670nanometers (nm). According to another embodiment, the light sources 116comprises three lasers including a red diode laser operable to emit abeam at approximately 635 nm; a green diode-pumped solid state (DPSS)laser such as frequency-doubling or second harmonic generation (SHG)laser excited by an infrared laser diode at about 1064 nm wavelength,the green SHG laser being operable to emit a green beam of light atabout 532 nm; and a blue laser diode operable to emit light at about 473nm. While some lasers may be directly modulated, other lasers mayrequire external modulation such as an acousto-optic modulator (AOM) forinstance. In the case where an external modulator is used, it isconsidered part of the light source 116. Laser diode light sources areillustrated as part of integrated photonics module embodiments shownbelow.

The beam combining and shaping optics 118 are aligned to receive thebeams of light emitted by the light sources and to combine some or allof the beams into a single beam. The beam combining and shaping optics118 may also include beam-shaping optics such as one or morecircularizing lenses, collimating lenses, focusing lenses, relay lenses,and/or apertures and wavelength selecting optics such as birefringentfilters, gel filter, hot mirrors, etc. Additionally, while thewavelengths described have been in the optically visible range, otherwavelengths may be within the scope of the invention.

According to various embodiments, the scanner 120 may be formed usingmany known technologies such as, for instance, a rotating mirroredpolygon, a mirror on a voice-coil, a mirror affixed to a high speedmotor, a mirror on a bimorph beam, an in-line or “axial” gyrating scanelement, a MEMS scanner, or other type. A MEMS scanner may be of a typedescribed in U.S. patent application Ser. No. 10/984,327, entitled MEMSDEVICE HAVING SIMPLIFIED DRIVE, for example, incorporated herein byreference.

In the case of 1D scanners, the scanner may include a first beamdirector driven to scan the output beam along a single axis and a secondbeam director driven to scan the output beam in a second axis. In such asystem, both scanners are referred to as a scanner 120. In the case of a2D scanner, scanner 120 is driven to scan output beam 125 along aplurality of axes (optionally through final optics 126) to sequentiallyilluminate pixels in the field of view to produce the image 128.

For compact and/or portable display systems 101, a MEMS scanner is oftenpreferred, owing to the high frequency, durability, repeatability,and/or energy efficiency of such devices. A bulk micro-machined orsurface micro-machined silicon MEMS scanner may be preferred for someapplications depending upon the particular performance, environment orconfiguration. One exemplary MEMS scanner embodiment is presented inperspective in FIG. 12. Other embodiments may be preferred for otherapplications.

A 2D MEMS scanner embodiment of the scanner 120 scans one or more lightbeams 125 at high speed in a pattern that covers an entire projectionscreen or a selected region of a projection screen within a frameperiod. A typical frame rate may be 60 Hz, for example. Often, it isadvantageous to run one or both scan axes resonantly. In one embodiment,one axis is run resonantly at about 19 KHz while the other axis is runnon-resonantly in a sawtooth pattern to create a progressive scanpattern. A progressively scanned bi-directional approach with a singlebeam, scanning horizontally at scan frequency of approximately 19 KHzand scanning vertically in sawtooth pattern at 60 Hz can approximate anSVGA resolution. In one such system, the horizontal scan motion isdriven electrostatically and the vertical scan motion is drivenmagnetically. Alternatively, both the horizontal scan may be drivenmagnetically or capacitively. Electrostatic driving may includeelectrostatic plates, comb drives or similar approaches. In variousembodiments, both axes may be driven sinusoidally or resonantly.

The integrated photonics module 102 may be embodied as monochrome, asfull-color, or hyper-spectral. In some embodiments, it may also bedesirable to add color channels between the conventional RGB channelsused for many color displays. Herein, the term grayscale and relateddiscussion shall be understood to refer to each of these embodiments aswell as other methods or applications within the scope of the invention.In the control apparatus and methods described below, pixel gray levelsmay comprise a single value in the case of a monochrome system, or maycomprise an RGB triad or greater in the case of color or hyperspectralsystems. Control may be applied individually to the output power ofparticular channels (for instance red, green, and blue channels) or maybe applied universally to all channels, for instance as luminancemodulation.

The system resources 104 may include a power supply 132, user interface134, video interface 136, and packaging 138. The video interface mayinclude, for example a USB port, Bluetooth, Wi-Fi, Firewire, SD socket,IRdA port, or other interface to receive images for projection. Thevideo interface may communicate with the video control electronics 106using a variety of interfaces including Bluetooth, USB, etc., accordingto various embodiments. According to an embodiment, the system resourcesinclude an operating system capable of retrieving images or video from apassive storage device such as a USB drive, SD card or other memory, andprojecting images or video individually or in a slide show. This may beuseful, for example, for accepting a memory device from a digital cameraand projecting recently captured images to friends and family.

FIGS. 2, 3, and 4 are a series of perspective views of an integratedoptical engine portion 114 of an integrated photonics module 102according to an embodiment. An optical frame 202 supports three lightsources 204, 206, and 208; beam shaping optics (not shown); a beamcombiner 210; and a beam scanner 120 in optical alignment with oneanother to deliver a scanned modulated beam through an output face 212as shown. FIG. 5 provides dimensions for the integrated optical engineportion 114 of the integrated photonics module 102 according to anembodiment. As may be seen, the outer dimensions of the package (11.5 mmhigh by 23 mm deep by 40 mm wide, or less than ½ by 1 by 1⅝ inches) maybe very compact, allowing for easy integration into evensize-constrained portable electronic devices. This amounts to just 10.6cubic centimeters (0.65 cubic inches). As may be seen in figures below,this package provides relatively generous spacing between light sources.Further shrinking of the package in width is possible by creatingtighter spacing between the light sources.

According to some embodiments, the optical frame 202 may be thermallycoupled to the light sources 204, 206, and 208. Such thermal couplingmay allow the optical frame to act as a heat sink for the light sources.A thermistor, thermocouple, etc. may be thermally coupled to the opticalframe 202 to monitor temperature. The light output may be modified, shutdown, etc. if it is determined the temperature is out of an operatingrange.

FIGS. 6, 7, and 8 are a series of perspective cut-away views of theintegrated optical engine portion 114 portion of the integratedphotonics module 102 corresponding to the respective perspectives ofFIGS. 2-4 according to an embodiment. The illustrative beam shapingoptics 602, 604, and 606 may be seen positioned to receive light beamsfrom the respective light sources 204, 206, and 208. When the lightsource 204 includes a SHG laser, its corresponding beam shaping optics602 may include an infrared-excluding filter configured to preventinfrared pump light from exiting the light source 204. The respectivemirrors 608, 610, and 612 of the beam combiner 210 may be seen alignedto receive and direct beams of light from the light sources 206, 204,and 208 along the long axis of the beam combiner as a composite beam. Aselective fold mirror 614 is aligned to receive the composite beam anddirect it toward the mirror 616 of a MEMS scanner 618 component of thescanner 120. The selective fold mirror 614 may be aligned to launch thecomposite beam toward the scan mirror 616 from a direction substantiallynormal to the nominal mirror (center crossing) position. Such anarrangement may be useful to minimize geometric distortion in thescanned beam. Additional components according to embodiments includingmagnets 620 and interface cable 622 of the scanner 120 may also be seenin FIGS. 6-8.

FIG. 9 is a view showing the alignment of some of the principal opticalcomponents of the integrated photonics module of FIGS. 2-8 according toan embodiment. The components are as described above. The scanned beamexit face 212 in the beam combiner 210 of the integrated photonicsmodule may be seen.

FIG. 10 is a view of an optical frame 202 for the integrated photonicsmodule of FIGS. 2-8 according to an embodiment. According to anembodiment, the optical frame 202 may be manufactured from a metal suchas aluminum, titanium, etc. using a die-casting process. Alternatively,the optical frame 202 may comprise an injection molded plastic such as aglass-filled or other dimensionally-stable plastic. Optionally,secondary machining operations may be performed on the optical frame toprovide precise dimensional tolerances and or achieve other designpreferences. According to other embodiments, the optical frame 202 maybe manufactured using machining and/or sheet metal forming operations.Alternative materials and manufacturing processes will be apparent tothose skilled in the art and, unless specified otherwise, are intendedto fall within the scope of various embodiments. The optical frame 202may optionally be a one- or two-piece component as shown. Optionally,the optical frame 202 may comprise a larger number of components suchas, for example, a printed circuit board and components thereon,separate emitter/optics/combiner and scanner portions, etc.

The optical frame 202 may include bores 1002, 1004, and 1006 formed toreceive respective light sources 206, 204, and 208 and associated beamforming optics. The optical frame 202 may further include one or morelocation faces 1008 (1008 a, 1008 b, 1008 c, and 1008 d shown) formed toreceive and align a selective fold mirror, beam combiner, etc. A face1010 may be formed to receive a scanner (not shown) in alignment.Additionally, other mounting faces and features 1012 may be formed alongother axes.

According to some embodiments, the optical components may bemechanically clamped into the optical frame 202 with a cover portion(not shown) such as with fasteners (e.g. screws, rivets, etc), usingadhesive, by clamping, etc. According to other embodiments, one or moreof the optical components may be mechanically coupled to the opticalframe 202 using discrete or integrated fastening technology, adhesive(e.g. UV-cured optical adhesive), etc. In cases where components aredirectly coupled to the optical frame, a separate cover portion may beomitted, according to embodiments.

FIG. 11 is a perspective view of at least a portion of an integratedphotonics module including a mechanically-coupled circuit board 1102according to an embodiment. The circuit board 1102 may optionally form astructural portion of the integrated optical engine portion 114 of theintegrated photonics module 102. According to various embodiments, thecircuit board 1102 may contain one or more of sensors, light sourcedrivers, scanner controller, video controller electronics, and memory.As described above, the various sensors, light source drivers, scannercontroller, video controller electronics, and memory may take many formsincluding but not limited to a conventional microprocessor ormicrocontroller and associated components, a single integrated ASIC, twoor more ASICs, two or more ASICs plus one or more microprocessors suchas DSPs or conventional CISC or RISC microprocessors, memory such asvideo memory ICs, other integrated components, discrete components, andsoftware. In addition, a media module operable to convert a video signalinto a preferred format may be integrated into the controller and ontothe circuit board 1102. The MEMS scanner 120 and the light sources 116may be interfaced directly to the circuit board 1102.

FIG. 12 is a perspective view of a micro-electro-mechanical system(MEMS) scanner 618 that may be used to scan a beam of light in anintegrated photonics module according to an embodiment. The MEMS scanner618 may be formed from a layer of a single-crystal silicon wafer 1202and a layer of a wafer of a dielectric material such as pyrex glass1204, the wafers hermetically joined according to conventionalsilicon-on-insulator (SOI) technology. The layers may be partially- andthrough-etched to form a bulk micromachined MEMS scanner usingtechniques such as potassium hydroxide (KOH) etching, deep reactive ionetching (DRIE), combinations thereof, etc. According to one embodiment,the torsional hinges and mirror scan plate (described below) arepartially etched to form thinned structures tuned to provide desiredresonance frequencies, energy storage, mass, spring constant, etc.

The MEMS scanner 618 includes a scanning mirror 616 formed from areflective metal or dielectric quarter-wave stack on a scan plate. Themirror and scan plate may be suspended on torsional fast-scan hinges1206 a and 1206 from a gimbal ring 1208. The torsional fast-scan hinges1206 a and 1206 b are operable to allow rotation of the mirror 606relative to the gimbal ring 1208 around an axis defined by theircenterlines. The gimbal ring is, in turn, suspended on torsionalslow-scan hinges 1210 a and 1210 b from a mounting frame 1212. Thetorsional slow-scan hinges 1210 a and 1210 b are operable to allowrotation of the gimbal ring and mirror relative to the mounting frame1212 around an axis defined by their centerlines. An actuator comprisingan electromagnetic coil 1214 is formed on the gimbal ring for drivingrotation around the slow-scan and fast-scan axes. A signal containing acomposite of slow-scan and fast-scan waveform may be received from theMEMS controller via a MEMS amplifier (not shown) via leads 1216 (andinterface cable 622, not shown). The actuator 1214 forms a compositeperiodic magnetic field that pushes and pulls against an externalmagnetic field formed by scanner magnets 620 (not shown, but visible inFigures above).

Because the gimbal ring 1208 is directly driven, the slow scan drive mayprovide an arbitrary drive waveform selected to exclude frequencies thatmay excite the fast scan. According to an embodiment, the slow scanwaveform may approximate a sawtooth wave or an asymmetric triangle waveat a periodic frequency corresponding to a frame rate such as 60 Hz. Thesawtooth slow scan waveform may thus be operable to provide a verticalframe scan with retrace through a desired angle.

The fast scan drive signal includes a periodic waveform, such as a sinewave for example, selected to correspond to a resonance frequency of themirror and scan plate 616. Slight asymmetries in the system are operableto transmit minute fluctuations in the motion of the gimbal ring 1208 atthe fast-scan frequency to the mirror 616 via the fast-scan flexures1206 a and 1206 b. The minute fluctuations in motion are amplifiedthrough resonance to provide a desired fast-scan angle.

The MEMS scanner 618 may further include various sensors to providefeedback to the MEMS controller. These may include piezo-resistor (PZR)strain sensors in the torsional hinges, temperature junctions orthermistors, etc. According to an embodiment, the mirror and scan plate616 have a diameter of about 1.2 mm, sufficient to receive the compositeinput beam without beam clipping.

The MEMS scanner 618 is shown with its scan plate and the scanningmirror 616 formed thereon at one un-powered or “rest” position.According to embodiments, the mirror may be tilted at a powered restposition in the slow-scan axis by applying a DC bias to the actuator.The DC bias may apply a nominal “tilt” to the gimbal ring 1208 about theslow scan axis define by the slow scan torsional hinges 1210 a, 1210 b.Alternative embodiments of MEMS scanners may be operable to create apowered rest plane of the mirror 616 in both axes. For example, a MEMSscanner may be formed with actuators 1214 formed on the scan plate. A DCbias in an actuators on the scan plate may be operable to apply anominal tilt to the mirror 616 about the fast scan axis defined by thetorsional hinges 1206 a, 1206 b, in addition to the actuator 1214 on thegimbal ring 1208 providing a rest tilt relative to the slow scan axis.

Such a nominal tilt in rest position may be used, for example, to moreprecisely align the mirror 616 to the integrated optical assembly (notshown).

FIG. 13 is a diagram illustrating exemplary beam shapes 119, 125 andbeam shaping optics 602, 604, 606 for three configurations 1302, 1304,1306 corresponding to three applications for an integrated photonicsmodule according to embodiments.

According to a first configuration 1302 corresponding to aheads-up-display, the beam 119, 125 may be focused to a waist 1308 at adistance approximately 100 mm from the output face 212 (not shown) ofthe integrated photonics module. According to various embodiments, theemitted beams from a plurality of light sources 204, 206, 208 may becombined by a beam combiner 210 into a modulated composite beam, and themodulated composite beam scanned by a beam scanner 120 as a scannedmodulated beam 125, as indicated by the diagram. The exemplary distanceof 100 mm may correspond to the distance to an exit pupil expander (notshown). In such applications, the exit pupil expander may typically beinserted prior to final optics 126 (not shown) to provide an expandedexit pupil or eye-box in which an image may be projected onto a viewer'sretina.

According to a second configuration 1304 corresponding to a portablescanned beam video projector, the beam 119, 125 may be focused to awaist 1308 at a distance approximately 500 mm from the output face 212(not shown) of the integrated photonics module. According to variousembodiments, the emitted beams from a plurality of light sources 204,206, 208 may be combined by a beam combiner 210 into a modulatedcomposite beam, and the modulated composite beam scanned by a beamscanner 120 as a scanned modulated beam 125. According to variousembodiments, final optics 126 may be placed in the beam path asindicated by the diagram. The exemplary distance of 500 mm maycorrespond to a nominal working distance from a projection surface.

According to a third configuration 1306 corresponding to a head-wornscanned beam or retinal display, the beam 119 may be focused to a waist1308 at a distance approximately 10 mm from the output face 212 (notshown) of the integrated photonics module. According to variousembodiments, the emitted beams from a plurality of light sources 204,206, 208 may be combined by a beam combiner 210 into a modulatedcomposite beam 119, and the modulated composite beam launched into anoptical fiber for transmission to the head-worn portion of the display.The exemplary distance of 10 mm may correspond to a distance between theoutput face of the integrated photonics module and the fiber optic inputcoupler. According to various embodiments, the optical fiber, which maybe a single mode optical fiber, conveys the modulated composite beam 119to a distal end near the eye of a viewer. The light may typically exitthe distal end of the optical fiber at a divergence angle thatsubstantially corresponds to the convergence angle made by the beam atthe input or proximal end. The light that exits the distal end of theoptical fiber (not shown) may be focused to a distance corresponding tothe distance to the viewers eye, scanned in a periodic pattern by a beamscanner mounted distally (not shown), and relayed to the viewer's eye byfinal optics (not shown).

One general observation that may be drawn from the diagrams of FIG. 13is that an integrated photonics module may be adapted to operate in avariety of applications. Additionally or alternatively, variants of anintegrated photonics module design may be adapted to a variety ofapplications, some of which are indicated in FIG. 13. FIGS. 14-18 andother description herein, literal and inherent, illustrate someapproaches to providing an integrated photonics module havingcommonality or commonality of design across a range of applications.

FIG. 14 is a diagram illustrating discrete and integrated variants ofbeam shaping optics for an integrated photonics module according toembodiments. A heads-up display application 1302 may, according to anembodiment, use some or all of a circularizing lens 1402, a collimationlens 1404, a top hat lens 1406, and a focus lens 1408 to shape its beam.The optional circularizing lens 1402 may provide astigmatic correctionto convert the output of many lasers, which may have differentdivergences in each of two axes, to a radially symmetric beam withsubstantially equal divergence in any axis. Such a lens may providecircularization with minimal loss of optical power. Additionally oralternatively, a clipping aperture may be used in the system. Acollimating lens 1404 provides a beam shape with substantially parallelsides for introduction to a top hat lens 1406. The top hat lens 1406converts the Gaussian energy distribution of the input beam to an outputbeam with a top hat shape having substantially equal power across itscross section. A focus lens 1408 focuses the beam to a working distanceas indicated above.

Top hat beams convolve through a sinc-shaped energy distribution beforeconvolving back to a top hat energy distribution. Accordingly, it may bedesirable to select a focal length for the top hat lens 1406 to producea convolved top hat function at a viewing distance. The focal length ofthe focus lens 1408 may be selected to produce a waist at an EPE, whichmay for example be an ordered micro-lens array (MLA). The EPE producesbeamlets in the far field to provide an expanded region over which thevideo image may be received by the viewer's retina. By selecting a tophat shaped composite scanned beam, the beamlets produced by the EPE mayalso be top hat shaped (after convolution through a sinc energydistribution) within the range of desired viewing distances. The top hatshaped beamlets “tile” with one another and reduce or eliminate visiblevariations in power across the eye-box.

As may be seen in the HUD application 1302 represented by the topdiagram in FIG. 14, the circularizing, collimation, top hat, and focuslenses 1402, 1404, 1406, and 1408 may be combined into one or moreintegrated lenses 1410.

A portable projector application 1304 may, according to an embodiment,use some or all of a circularizing lens 1402 and a focus lens 1408 toshape its beam. As with the HUD application 1302, the optionalcircularizing lens 1402 may provide astigmatic correction to convert theoutput of many lasers, which may have different divergences in each oftwo axes, to a radially symmetric beam with substantially equaldivergence in any axis. Such a lens may provide circularization withminimal loss of optical power. Additionally or alternatively, a clippingaperture may be used in the system. A focus lens 1408 focuses the beamto a working distance as indicated above. Optionally, other lenses suchas collimation and top hat lenses may also be used in portable projectorembodiments.

As may be seen in the portable projector application 1304 represented bythe middle diagram in FIG. 14, the circularizing and focus lenses 1402and 1408 may be combined into one or more integrated lenses 1412.

A head mounted display application 1306 may, according to an embodiment,use some or all of a circularizing lens 1402 and a focus lens 1408 toshape its beam. As with the HUD and portable projector applications 1302and 1304, the optional circularizing lens 1402 may provide astigmaticcorrection to convert the output of many lasers, which may havedifferent divergences in each of two axes, to a radially symmetric beamwith substantially equal divergence in any axis. Such a lens may providecircularization with minimal loss of optical power. Additionally oralternatively, a clipping aperture may be used in the system. A focuslens 1408 focuses the beam to a working distance as indicated above.Optionally, other lenses such as collimation and top hat lenses may alsobe used in head mounted display embodiments.

As may be seen in the head mounted display application 1306 representedby the bottom diagram in FIG. 14, the circularizing and focus lenses1402 and 1408 may be combined into one or more integrated lenses 1414.

The integrated lens 1416 is representative of a physical embodiment ofthe integrated lenses 1410, 1412, and 1414 described above.

FIGS. 15-17 are indicative of an approach for providing at least acommon portion in an integrated photonics module that may be used in avariety of applications by distributing the beam shaping function acrossa plurality of optical elements. FIG. 15 is a diagram illustrating aportion of an integrated photonics module for a portable scanned beamprojector 1502 according to an embodiment. The beams from the lightsources 116 are shaped by the beam shaping optics 602, 604, and 606, andcombined by the beam combiner 210 to form a modulated composite beam 119as described above.

FIG. 16 is a diagram illustrating the use of the integrated photonicsmodule portion for a portable projector 1502 of FIG. 15 to provide aportion of an integrated photonics module for a HUD 1602 havingdiffering beam shape requirements as indicated especially by FIG. 13,according to an embodiment. As shown in FIG. 16, the integratedphotonics module portion 1502 may be combined with a composite beamshaping optical assembly 1604. According to the illustrative embodiment,the integrated photonics module portion 1502 is operable to provide amodulated composite beam having characteristics appropriate for aportable scanned beam video projector, for example having a beam with awaist distance of about 500 mm, as illustrated by FIG. 13. The beam maythen be introduced to a series of lenses including a collimation lens1404, a top hat lens 1406, and color-balanced focusing optics 1606. Theseries of lenses 1404, 1406, and 1606, referred to in combination as anoptical assembly 1604 is configured to convert the beam from a shapeappropriate for a portable scanned beam video projector to a shapeappropriate for a HUD, for example one having a top hat powerdistribution and a focus distance of 100 mm.

FIG. 17 is a diagram illustrates the integration of the optical assembly1604 into a composite lens 1704 to form an integrated photonics moduleportion 1702 for a HUD according to an embodiment.

FIG. 18 is a perspective view of at least a portion of an integratedphotonics module 114 showing light transmission paths and the placementof optional adaptor optics according to an embodiment. The integratedphotonics module 114 includes a portion 1502 configured for a portablescanned beam video projector and an adaptor optic 1704 configured toreceive the modulated composite beam from the portion 1502 and produce amodulated composite beam 119 having different characteristics. Accordingto the embodiment, the portion 1502 and the adaptor optic 1704 comprisea portion of an integrated photonics module 1702 configured for aheads-up display. As described above the modulated composite beam isscanned in a periodic pattern by the scanner 120 to form the modulatedscanned beam 125 that is operable, in this example, to provide a videoimage to the operator of a vehicle equipped with a HUD comprising theintegrated photonics module including the module 114.

FIG. 19 is a diagram illustrating the relationship of the light sources204, 206, and 208 and the beam combiner 210 of at least a portion of anintegrated photonics module according to an embodiment. FIG. 19 includesa side view of a beam combiner 210 for combining separate R, G, and Blight beams 1902, 1904, and 1906 into a single, composite light beam119, and a diagram of an RGB beam source 114 according to an embodiment.

The beam combiner 210 includes three sections 1908, 1910, and 1912,which are bonded together and which are made from a transparent materialsuch as glass or polymer suitable for optical applications. The combiner210 also includes an input face 1914 having a length of 3W and arectangular cross section in the X-Z plane, and includes an output face1916 having a height of W and a square cross section in the Y-Z plane.In one embodiment, W=5.5 millimeters (mm), and in another embodimentW=3.5 mm. Both the input face 1914 and the output face 1916 are flat,optical-quality surfaces. The manufacture of the combiner 210 isdiscussed U.S. patent application Ser. No. 10/828,876, entitledAPPARATUS AND METHOD FOR COMBINING MULTIPLE ELECTROMAGNETIC BEAMS INTO ACOMPOSITE BEAM, commonly assigned herewith and incorporated by referenceherein.

The first section 1908 has a parallelogram-shaped cross section in theX-Y plane with a height and width of W and includes a segment input face1918, which forms part of the combiner input face 1914, and a reflectorface 608 for reflecting the R beam 1902 toward the combiner output face1916. In one embodiment, the face 608 is made reflective by applicationof a conventional optical coating. One can select the reflective andtransmissive properties of this coating (and the other coatingsdiscussed below) according to the parameters of the beam-combinersystem. The angle α between the input face 1918 and the reflector face608 is an acute angle. In a preferred embodiment, α=45° to allow the Rbeam 1902 to have a maximum width in the X dimension equal to W. Thatis, if α=45°, then all portions of a W-width R beam will project ontothe reflector face 608 as long as the R beam is properly aligned withthe input face 1918. If, however, the combiner 210 is designed for an Rbeam 1902 having a width less than W, then the region of the face 608that is reflective can be limited to the area that the R beam willstrike. Alternatively the angle α can be made greater than 45°. Butbecause the angle α is the same for all of the segments 1908, 1910, and1912, one should consider the effect on the other segments 1910 and 1912before altering the value of α. Furthermore, if a does not equal 45°,then the angle of the R beam from the beam source 114 is adjusted suchthat the reflected R beam remains normal to the output face 1916.

Similarly, the second section 1910 has a parallelogram-shaped crosssection in the X-Y plane with a height and width of W and includes asegment input face 1920, which forms part of the combiner input face1914, and includes a reflector face 610, which lies along an interfacebetween the sections 1908 and 1910 and passes the reflected R beam 1902and reflects the G beam 1904 toward the combiner output face 1916. Inone embodiment, the face 610 is made reflective by application of aconventional optical coating to either or both the face 610 and the faceof the section 1908 that interfaces with the face 610. The angle αbetween the input face 1920 and the reflector face 610 is an acuteangle, and is preferably equal to 45° to allow the G beam 1904 to have amaximum width in the W dimension equal to W. If, however, the combiner210 is designed for a G beam 1904 having a width less than W, then theregion of the face 610 that is reflective can be limited to the areathat the G beam will strike. Alternatively the angle α can be madegreater than 45°. But because the angle α is the same for all of thesegments 1908, 1910, and 1912, one should consider the effect on theother segments 1908 and 1912 before altering the value of α.Furthermore, if α does not equal 45°, then the angle of the G beam fromthe beam source 114 is adjusted such that the reflected G beam remainsnormal to the output face 1916.

The third section 1912 has a triangular-shaped cross section in the X-Yplane and includes the combiner output face 1916, a segment input face1922, which has a width of W and which forms part of the combiner inputface 1914, and a reflector face 612, which lies along an interfacebetween the sections 1910 and 1912 and passes the reflected R and Gbeams 1902 and 1904 and reflects the B beam 1906 toward the combineroutput face. In one embodiment, the face 612 is made reflective byapplication of a conventional optical coating to either or both the face612 and the face of the section 1910 that interfaces with the face 612.The angle α between the input face 1922 and the reflector face 612 is anacute angle, and is preferably equal to 45° to allow the B beam 1906 tohave a maximum width in the X-dimension equal to W. If, however, thecombiner 210 is designed for a B beam 1906 having a width less than W,then the region of the face 612 that is reflective can be limited to thearea that the B beam will strike. Alternatively the angle α can be madegreater than 45°. But because the angle α is the same for all of thesegments 1908, 1910, and 1912, one should consider the effect on theother segments 1908 and 1910 before altering the value of α.Furthermore, if α does not equal 45°, then the angle of the B beam fromthe beam source 114 is adjusted such that the reflected B beam is normalto the output face 1916. Moreover, an angle β between the section inputface 1922 and the output face 1916 is substantially a right angle in apreferred embodiment.

FIG. 20 is a diagram illustrating light transmission in at least aportion of an integrated photonics module according to an embodiment2001. Light sources 116, which may include three light sources 204, 206,and 208, are configured to launch beams of modulated light through theirrespective beam shaping optics 602, 604 and 606 toward a beam combiner210. The light sources may be configured to emit polarized beams oflight. Alternatively, the beam shaping optics 602, 604, and/or 606 mayinclude polarizers configured to provide S-polarized light to the beamcombiner 210 as shown. Optionally, the mirrors 608, 610, and 612 may beconfigured to combine the S-polarized components of the input beams andpass the P-polarized components toward a light trap (not shown). Therespective mirrors 608, 610, and 612 of the beam combiner combine thebeams of modulated light from the emitters 206, 204, and 208 into amodulated composite beam 119 of S-polarized light. Adaptor optics 1704may optionally be inserted into the beam path to receive light from theoutput face 1916 of the beam combiner.

A selective fold mirror 614 comprising a polarizing beam splitterdirects the modulated composite beam 119 toward the mirror 616 of ascanner 120. The selective fold mirror 614 may be aligned to launch thecomposite beam toward the scan mirror 616 from a direction substantiallynormal to the nominal mirror (center crossing) position. Such anarrangement may be useful to minimize geometric distortion in thescanned beam.

As an alternative to providing S-polarized light in the beam combiner210, some or all of the polarization of the beam may be provided by thepolarizing beam splitter 614, the polarizing beam splitter beingoperative to direct the S-polarization component of the modulatedcomposite beam 119 toward the scan mirror 616 and pass the P-componentof the light toward a light trap (not shown).

The polarizing beam splitter 614 is configured to preferentially reflectS-polarized light and thus reflects S-polarized light toward the scanner120. The S-polarized modulated composite beam passes through apolarization rotator 2002 on its path toward the scan mirror 616. Thepolarization rotator may be configured as a quarter-wave plate operativeto convert the S-polarized light to circularly polarized light before itimpinges upon the scan mirror 616. As described above, the scanner 120is operable to scan the beam in a periodic pattern across a field ofview to produce a scanned modulated beam of light 125. After beingreflected (and scanned) by the scanner mirror 616, the scanned beamagain passes through the polarization rotator 2002. The polarizationrotator converts the now circularly-polarized beam from the scan mirrorto P-polarized light.

The P-polarized light propagates toward the polarizing beam splitter614. The polarizing beam splitter 614 is configured to preferentiallypass P-polarized light and thus allows the P-polarized scanned beam 125to pass toward the FOV.

As an alternative to using polarized light, the system of FIG. 20 mayuse non-polarized or elliptically polarized light. In such analternative embodiment, the fold mirror 614 may comprise a selectivereflector such as a half-silvered mirror. A portion of the impingingbeam 119 passes through the fold mirror 614, for example toward a lighttrap (not shown), and a portion of the light energy is directed towardthe scanner mirror 616. The polarization rotator may be omitted in thealternative embodiment. The scanned beam 119 again impinges on thehalf-silvered mirror 614 and a portion of it passes through toward theFOV. The portion reflected may be reflected back toward the lightsources and/or toward light traps.

Several alternative embodiments to the configuration of FIG. 20 arepossible. FIG. 21 is a diagram illustrating light transmission accordingto another embodiment 2101 that launches the composite beam 119 towardthe scanner 120 at an oblique angle. The scanned beam 125 passes towardthe FOV in a pattern that has some amount of keystone distortioncompared to the approach of FIG. 20. According to some embodiments themodulated composite beam 119 need not be polarized and the fold mirror614 need not be a selective reflector when the scanned beam does notpass through the fold mirror again.

FIG. 22 illustrates an embodiment 2201 wherein the scanner 120 isconfigured to lie on the opposite side of the beam combiner from thelight sources 116. The scanned beam of light thus passes toward the FOVin a direction “behind” the light sources 116.

FIG. 23 is a diagram illustrating an embodiment 2301 wherein the foldmirror may comprise a polarizing beam splitter configured as a solidoptic.

FIG. 24 is a diagram illustrating an embodiment 2401 wherein the foldmirror 614 is integrated into the beam combiner 210. The illustratedembodiment illustrates the fold mirror 614 as a polarizing beamsplitter. As described above, the fold mirror reflects a firstpolarization of light toward the scanner 120. The polarization rotator2002 is configured to rotate the polarization 90 degrees in adouble-pass to and from the scanner 120, preferentially reflecting inputenergy toward the scanner and preferentially passing the scanned beamtoward the FOV.

The embodiment 2401 uses a fold mirror 614 that is configured in a planeparallel to the plane of the beam combining mirrors 608, 610, and 612.

FIG. 25A is a diagram illustrating another embodiment 2501 wherein thefold mirror 614 is integrated into the beam combiner 210. The embodimenthas a configuration that outputs the scanned beam 125 in a forwarddirection relative to the light sources 116. The plane of the foldmirror 614 is configured to be substantially at a right angle to theplanes of the combining mirrors 608, 610, and 612.

FIG. 25B is a diagram illustrating an embodiment 2502 comprising least aportion of an integrated photonics module including non-imagingdetectors. The embodiment 2502 includes a light detection module 2504that may comprise an optional light diffuser 2506, an optional spacer2508, optional reflective sidewalls 2510, and non-imaging lightdetectors 2512. As noted above, a P-polarized scanned beam 125, whichmay optionally be made non-modulated, is scanned across a FOV. A portionof the scanned beam 125 may be scattered from objects in the FOV asscattered light 2514. Typically, for non-specular objects, the scatteredlight 2514 may be non-polarized or elliptically polarized. The scatteredlight may also typically formed as a bundle of parallel or divergingrays that substantially fill the selective fold mirror 614. Theselective fold mirror 614 receives the scattered beam 2514 and reflectsits S-component polarization as indicated toward the optional lightdiffuser 2506. The optional light diffuser 2506 is configured to scatterthe received rays over a scattering angle as illustrated. The scatteredrays travel through the spacer 2508 to impinge on the light detectors2512. A portion of the scattered rays may be scattered at anglesunlikely to be received by a detector. Optional reflective sidewalls2510 may be used to redirect such “lost” energy toward the detectors2512. The detectors 2512, which may for example be configured to receivewavelengths corresponding to the emission wavelengths of the lightsources, are operable to convert received light energy into electricalsignals. According to an embodiment, an integrated photonics module 2502may be configured to emit red, green, and blue laser light as acomposite scanned beam 125 with the detectors 2512 being filtered toreceive corresponding red, green, and blue scattered light from the FOV.

In operation, the electrical signals from the detectors 2512 may be readsynchronously with pixel scanning to produce a video image of the FOV.

One or more optional detectors 2516 may be configured to receive aP-polarization component from the FOV, optionally through one or morefocusing lenses. If the mirrors 608, 610, and 612 of the beam combiner210 are made to be wavelength-selective mirrors, then the signalreceived by the optional detector(s) 2516 may be operable to receivelight from the FOV and generate a corresponding electrical signal thatis not attributable to the scanned beam. Such light may be used, forexample, to determine ambient lighting at the FOV, which may, in turn,be used to determine brightness, color balance, etc. for the lightemitters.

FIG. 25C is a diagram illustrating an embodiment 2503 comprising least aportion of an integrated photonics module including a focal planedetector array. The embodiment 2503 includes a light detection module2518 that may comprise a lens or lens system 2520, an aperture 2522, aspacer block 2524, and a focal plane detector array 2526 such as a CCDor CMOS pixelated array, for example.

As noted above, a P-polarized scanned beam 125, which may optionally bemade non-modulated, is scanned across a FOV. A portion of the scannedbeam 125 may be scattered from objects in the FOV as scattered light2514. Typically, for non-specular objects, the scattered light 2514 maybe non-polarized or elliptically polarized. The scattered light may alsotypically formed as a bundle of parallel or diverging rays thatsubstantially fill the selective fold mirror 614. The selective foldmirror 614 receives the scattered beam 2514 and reflects its S-componentpolarization as indicated toward the lens 2520. The lens 2520 and theaperture 2522 are configured to form a conjugate image plane at the farsurface of the spacer 2524. The focal plane detector array 2526 isoperable to detect the conjugate image of the FOV and convert it to acorresponding electrical signal. In operation, the focal plane detectorarray 2526 may be read and flushed at a video frame rate, for exampleduring the flyback period of the scanner, to produce a video image ofthe FOV.

As indicated, the light so imaged may be formed from S-polarized lightselected for reflection by the selective fold mirror 614. Alternatively,a polarization rotator such as a detection path quarter wave plate (notshown) may be included, for example between the lens 2520 and theaperture 2522, to convert the plane-polarized light into circularlypolarized light. Such an approach may be advantageous, for example, toavoid polarization-dependent acceptance effects associated with thefocal plane detector 2526.

Alternatively to the illustrative embodiments of FIGS. 25B and 25C, thedetectors 2512 or 2526 may be configured to directly receive scatteredlight from the FOV rather than receive the scattered light from theselective fold mirror 614.

For applications that include light detection subsystems, such assubsystem 2504 or 2518 of the respective illustrative embodiments ofFIGS. 25B and 25C, the controller portions of the system may, of course,be configured and operable to received the electrical signals from thedetectors, convert analog signals to digital signals (or simply receivedigital signals for detectors with integrated ADCs), and assemble thereceived signals into video images, decode the received images intocorresponding data such as decoded bar code or OCR data, or otherwiseprocess the received signals to perform functions according to theapplication.

Some embodiments may use signals from the detectors 2512, 2526 to modifythe depth and/or timing of light source excitation to modify the scannedmodulated beam 125, for example to compensate for projection surfacenon-uniformity, distance, and/or ambient lighting. Some embodiments forperforming such compensation are disclosed in U.S. patent applicationSer. No. 11/284,043, entitled PROJECTION DISPLAY WITH SCREENCOMPENSATION, incorporated herein by reference.

Other embodiments may use signals from the detectors 2512, 2526 tocompensate for relative motion between the integrated photonics moduleand the projection surface, for example by modifying the phaserelationship between the motion of the beam scanner and the lightsources. Some embodiments for performing compensation are disclosed inU.S. patent application Ser. No. 11/635,799, entitled PROJECTION DISPLAYWITH MOTION COMPENSATION, incorporated herein by reference.

FIG. 25D is an embodiment 2527 corresponding to the embodiment 2501 ofFIG. 25A but wherein the scanner 120 is moved and the selective foldmirror 614 is oriented 90 degrees to pass the modulated composite beambut reflect the scanned beam 125. The at least a portion of themodulated composite beam 119 having S-polarization is launched from thebeam combiner 210 and passes through the selective fold mirror 614,through the polarization rotator 2002, and impinges upon the mirror 616of the scanner 120. The selective fold mirror 614 is aligned to passplane polarized light at the angle corresponding to that of themodulated composite beam 119 but reflect plane polarized light at theorthogonal polarization angle. The light rotator 2002 rotates thepolarization of the composite modulated beam 119 to circularpolarization on its way to the scan mirror 616. The scan mirror 616scans a reflection of the received beam of light in a periodic scanpattern through the polarization rotator 2002. The polarization rotatorrotates the polarization of the scanned beam from circular to planepolarization in an orientation substantially 90 degrees from that of themodulated composite beam 119 when launched from the beam combiner 210.The selective fold mirror 614 reflects the rotated scanned beam toward afield of view as scanned beam 125. In the example of FIG. 25D, thescanned beam 125 has S-polarization.

FIG. 25E is a diagram illustrating light transmission in at least aportion of an integrated photonics module 2529 according to anembodiment wherein the beam scanner is in a plane other than normal to anominal image projection direction. As with the embodiment of FIG. 25A,a polarization selective fold mirror 614, which may for example beconfigured as a polarizing beam splitter, is configured to direct themodulated composite beam of light in the direction indicated, toward apolarization rotator 2002. After passing through the polarizationrotator, the modulated composite beam of light is directed by a verticalfold mirror 2530 toward a beam scanning assembly 120 (partially obscuredby the mirror 2530) to impinge upon the scan mirror (not shown). Thescanned light then reflects back off the mirror 2530, through thepolarizing beam splitter 2002, and owing to its rotated polarization,through the selective fold mirror 614 and into the field of view as thescanned beam 125. According to one embodiment, the scanning mirror maybe configured to nominally be in the plane of the figure and hence lyingin a plane parallel to the nominal video projection axis. This approachmay offer, among other things, a thinner package in the dimension normalto the figure by allowing the permanent magnets of the scanning assembly120 to have a smaller outer size in the thickness dimension. The foldmirror 2530 may, for example, be a first surface metal, dielectric orother mirror that reflects substantially all the light impinging on it,at least over wavelengths corresponding to the output wavelengths of thelight sources 116. Of course, the position of the polarization rotator2002 may be varied, such as lying between the vertical fold mirror 2530and the scanner mirror (not shown).

FIG. 26 is a diagram illustrating an alternative embodiment 2601 whereinone of the light sources 204 is configured to launch its beam from theend of the beam combiner 210. As shown, its beam is launched throughbeam shaping optics 602 into an end opposite that of the fold mirror 614and the scanner 120. The embodiment 2601 may be especially advantageouswhen a physically large light source 204 is used.

FIG. 27 is a block diagram 2701 that includes a scanner controller 122comprising at least a portion of an integrated photonics moduleaccording to an embodiment.

According to the embodiment of FIG. 27, the scanner controller 122includes a scanner control ASIC 2702, a digital signal processor (DSP)2704 that is operable as a co-processor, supporting circuitry includingpower supply circuitry and memory, and flex circuit interconnects on aprinted circuit board. It may be noted that the embodiment of FIG. 27comprises a somewhat reduced level of integration compared to thescanner controller 122 of FIG. 1, in which a larger portion of controlfunctionality is integrated into the scanner control ASIC. According tovarious embodiments, the general theory of operation may be similar.

The scanner controller 122 is operable to drive a bi-axial MEMS scannerwhile providing appropriate timing information to video controllerelectronics 106 (not shown in FIG. 27) across the controllerinterconnection 2706. The scanner controller 122 may additionally beoperable to monitor ambient light levels and process auto-phasecalibration pulses and optionally relay these measurements to the videocontroller electronics.

As described and shown in FIG. 12, one scanner embodiment includes aMEMS scanner with magnetic drive on two axes and PZR sensors for bothaxes.

According to some embodiments, the scanner controller 122 may bephysically mounted near an optical engine portion 114 (not shown) of theintegrated photonics module. According to some embodiments such as ahead-mounted display as described above, the scanner controller 122 mayreside at a distal location near the scanner and may be physicallyseparated from the light source 116 (not shown) and at least a portionof the beam combiner and beam shaping optics 118 (not shown), the lightsource and beam shaping optics being configured to provide light to themirror of the MEMS scanner 618 from a proximal location through anoptical fiber to the distal location. Similarly, the video controllerelectronics 106 (not shown) may be mounted proximally near the lightsource and beam shaping optics and communicate with the distally mountedscanner controller 122 via an electrical, radio, or optical interface2706. In such an embodiment, it may be appropriate to mount the proximalportions of the integrated photonics module in a compact package thatmay be supported on a belt of the user and mount the distal portions ofthe system in a head-mounted package.

According to an embodiment, the DSP 2704 may provide slow scan FastFourier Transformation (FFT) processing to provide tuning and activedamping of the slow scan according to methods disclosed in U.S. patentapplication Ser. No. 11/266,584, entitled CIRCUIT FOR DRIVING A PLANTAND RELATED SYSTEM AND METHODS, incorporated herein by reference.Additionally, the DSP 2704 may provide functionality including one ormore of data communications with the video controller electronics;provide an interface for inputting calibration data for the MEMSscanner; pass parameters related to MEMS operation, auto-phase results,ambient brightness received from an ambient light sensor 2707,temperature received from temperature sensor 2708, etc. during normaloperation to the video controller electronics; an interface for fieldupgrade of firmware and software; task scheduling to ensure propertiming of critical operations; initialization and adjustment of fastscan oscillator registers; and open-loop temperature compensation of PZRsensors.

According to an embodiment, the scanner drive ASIC 2702 may be amixed-signal (analog and digital) device operable to provide MEMScontrol and provide automatic phase (auto-phase) correlation. Thescanner drive ASIC 2702 is operable to drive and control a bi-axial MEMSscanner 618. The bi-axial MEMS scanner 618 may be of a type that ismagnetically actuated on both axes with piezo-resistive (PZR) feedbacksensors. According to embodiments, the scanner drive ASIC 2702 mayinclude some or all of a variety of analog and digital functionsincluding, for example, providing user programmable current bias to thePZR feedback sensors with a PZR bias circuit 2709; providing aclosed-loop oscillator circuit 2710 operable to self-resonate the fastscan axis at a programmable amplitude, wherein AGC parameters may beadjustable allowing soft-start and tuning control options; provide aphase-locked loop (PLL) to create a slow scan sample clock (50 to 200kHz) that is synchronous with the fast scan resonant frequency, whereinthe multiplication factor may be programmable; provide a slow Scananalog to digital converter (ADC) 2712, wherein the slow scan inputsignal from the PZR amplifier is converted to a digital signal for theDSP processor 2704, wherein the ADC resolution may be 12 to 16 bits witha sample rate of 50 to 200 kHz; provide a slow scan digital to analogconverter (DAC) 2714, wherein the digital input signal for the slow scanwaveform is converted to an analog voltage and summed with the fast scandrive signal in a summing circuit 2716; provide a mirror status signalindicating the mirror angle is within the acceptable range; provide autophase sensor interface circuitry, wherein the circuitry operates withexternal photo detector(s) 2718 to condition the signals for the autophase function and measures the result; and provide an SPI serialdigital interface 2720 to communicate with the video controllerelectronics and allow read/write access to the internal registers forinitialization and monitoring.

The Fast Scan Oscillator block 2710 uses the PZR feedback signal tocreate a closed loop oscillator circuit. The oscillation frequency isdetermined by the resonant frequency of the scanner's fast scan axis.The amplitude of the oscillation is controlled by an AGC circuit thathas a programmable set point. The output from this loop is the FS SYNCwhich is a square wave at the FS resonant frequency that provides amaster synchronization signal to drive other system components. Theresonant frequency can vary from about 5 kHz to 40 kHz.

The slow scan position signal is received from the slow scan PZRs on theMEMS scanner 618, then amplified, filtered, and converted to digital inthe slow scan ADC 2712. This digital signal is sent to the DSP 2704 foranalysis. The DSP sends back a digital command signal that is convertedto analog in the slow scan DAC 2714. The analog slow scan drive signalis summed with the fast scan output in the summing circuitry 2716, andthe sum is sent to the external power amplifier 2722, which amplifiesthe summed analog signal to provide drive power to the scanner 618.

The Auto Phase circuitry 2724 works with one or more external opticaldetectors 2718. The scanned beam 125 (not shown) periodically crossesover the detector(s) 2718. The analog interface circuit 2724 produces apulse in response to the laser beam crossing, and the pulse length isthe information that is transmitted to the DSP 2704.

The fast scan oscillator 2710 is designed to be an analog‘self-resonant’ circuit that takes real-time position information fromthe MEMS PZR sensors, applies appropriate amplitude gain and phasedelay, and drives the mirror on resonance based on the mirror's feedbacksignal. Blocks with registers may be adjustable via the SPI processorinterface to provide MEMS characterization to accommodatedevice-to-device, lot-to-lot, and/or design-to-design tolerances.

As described in conjunction with FIG. 12, the fast scan motion of themirror is sensed with PZR strain sensors incorporated in the dieflexures on the MEMS scanner 618. The PZR sensors are provided anadjustable DC bias current by the PZR bias circuitry 2709. The biascurrent may be programmed with a software controlled value or with anexternal resistor. The PZR feedback differential sense signals areamplified in a low-noise differential pre-amplifier 2722 with anadjustable gain. The gain of the differential pre-amplifier 2722 may besoftware controlled or may be set with an external resistor to providecalibrated signal level (in peak-to-peak voltage) for a given mirrorangular deflection. The pre-amplifier 2722 output is filtered in theband pass filter 2725 that limits the noise bandwidth. The band passfilter 2725 may include a high pass filter followed by a low passfilter. The output signal of the band pass filter 2725 may be used todrive the scanner control system. At resonance, there is a 90 degreephase shift between the drive signal and the scanner motion. To sustainclosed loop oscillation, an extra 90 degrees of phase shift isintroduced into the loop with phase shifter 2726. The output of thephase shifter 2726 is ‘squared up’ in a comparator 2728 to create adigital fast scan synchronization signal. The fast scan synchronizationsignal may transmitted through a phase-locked loop output 2730 to theDSP 2704 and used as the primary time base for the slow scan drive aswell as the video signal processing that is performed in the videocontroller electronics 106 (not shown).

An automatic gain control (AGC) circuit may be used to maintain theoscillation amplitude at a very precise value. The loop may include anamplitude detector, a variable gain amplifier, and an AGC controller.The amplitude detector produces a DC voltage proportional to theamplitude of output of the band pass filter 2725. This voltage iscompared to the set point in the AGC controller, which implements aproportional-integral-differential (PID) control algorithm. The outputof the PID controller is used as the control voltage input of a variablegain amplifier 2732.

Mirror angle and frequency watchdog circuits 2734 monitor the output ofthe amplitude detector. If the amplitude exceeds a programmable setpoint, then the protection circuit issues a shutdown command thatimmediately disables the drive signal. A secondary safety circuitmonitors the amplitude of the drive signal, and prevents it fromexceeding a programmable value.

FIG. 28 is a block diagram 2801 for an integrated photonics modulecontroller including a video controller 106, a scanner controller 122,and a beam scanner 618 according to an embodiment.

The video controller 106 may be operable to perform some or all of:receiving a video signal from a system resource, optionally caching thereceived video data in video memory, converting the signal to a de-gammasignal, converting the de-gamma signal to an equalized color signal,buffering lines, performing interpolation to determine the value ofactual pixel positions scanned by the scanned beam as a function ofideal pixel positions in the received video signal, determiningluminance values for light sources, performing light source compensationand calibration, and passing compensated luminance values to lightsource drive circuitry synchronously with timing signals received from apixel clock, the pixel clock being generated by horizontal and verticalsynchronization pulses provided by the MEMS control module 122.

Optionally, the video controller 106 may include a media module 2802operable to convert a received video format into a preferred videoformat. According to one embodiment, the media module 2802 may beoperable convert a received analog video signal into a digital videosignal. According to other embodiments, the media module may be omittedor may be integrated as a system resource.

Aspects of several embodiments of operability of the integratedphotonics module controller 2801 are disclosed in U.S. patentapplication Ser. No. 11/316,326, entitled CIRCUIT FOR DETECTING A CLOCKERROR IN A SWEPT-BEAM SYSTEM AND RELATED SYSTEMS AND METHODS; U.S.patent application Ser. No. 11/316,683, entitled CIRCUIT FOR DETECTING ACLOCK ERROR IN A SCANNED IMAGE SYSTEM AND RELATED CIRCUITS, SYSTEMS, ANDMETHODS; U.S. patent application Ser. No. 10/630,062, entitled METHODAND APPARATUS FOR ILLUMINATING A FIELD-OF-VIEW AND CAPTURING AN IMAGE;U.S. patent application Ser. No. 10/441,916 entitled APPARATUS ANDMETHOD FOR BI-DIRECTIONALLY SWEEPING AN IMAGE BEAM IN THE VERTICALDIMENSION AND RELATED APPARATI AND METHODS; U.S. patent application Ser.No. 10/118,861 entitled ELECTRONICALLY SCANNED BEAM DISPLAY; U.S. patentapplication Ser. No. 10/933,033 entitled APPARATUSES AND METHODS FORUTILIZING NON-IDEAL LIGHT SOURCES; U.S. Pat. No. 6,661,393 entitledSCANNED DISPLAY WITH VARIATION COMPENSATION; and U.S. Pat. No. 6,445,362also entitled SCANNED DISPLAY WITH VARIATION COMPENSATION; allincorporated by reference herein.

FIG. 29 is a diagram illustrating the use of an integrated photonicsmodule 102 integrated into a mobile electronic device 2902 according toan embodiment 2901. As may be seen, the embodiment is configured to emita scanned beam of modulated light 125 in a direction nominally alignedwith the top or long dimension of the portable electronic device 2902.Optionally, the integrated photonics module 102 may be configured tolaunch the scanned beam in a different direction or in a plurality ofdirections. Alternatively, the integrated photonics module 102 may beconfigured to project an image onto the back side of a diffuser, thusforming a rear-projection screen.

The mobile device 2902 may comprise a range of device types includingbut not limited to a bar code scanner, a portable computer, a palm-topcomputer, a mobile telephone, a portable audio device such as an mp3player, a hard-disk based portable audio player, a portable videoplayer, a hard-disk based portable video player, a digital gamingsystem, a business presentation pointer, a laser pointer, a front- orrear-projection television, etc.

FIG. 30 is a diagram illustrating the use of an integrated photonicsmodule in an automotive heads-up display application according to anembodiment 3001. Alternative embodiments or applications may includeHUDs for aircraft, watercraft, motorcycles, etc.

A vehicle 3002 may include a dashboard 3004 that houses an instrumentcluster 3006. The instrument cluster includes an integrated photonicsmodule 201 with an optical portion 104 configured to project a scannedbeam image through relay optics 3008 that may include the windshield ofthe vehicle toward an occupant 3010. The system may be configured toprovide an exit pupil or eye-box 3012 corresponding to the position ofone or both eyes 130 of the occupant 3010.

Such a system may be used to present a variety of information to theviewer including but not limited to a low-light forward image, vehiclegauge information, a map or driving directions, entertainment content,advertising content that may optionally be related to the location ofthe vehicle 3002, emergency information, etc.

FIG. 31 is a perspective view of a portable scanned beam projectiondisplay 3102 using an integrated photonics module according to anembodiment 3101. As illustrated in FIG. 31, the portable projectiondisplay 3102 may be held in the hand of a user 3010 according to aconfiguration of an embodiment. An output optical element 3104 is shownconfigured to project an image through a scanned beam 125 in a direction3106 aligned longitudinally with the body of the portable videoprojector 3102 as desired by the user.

According to another embodiment, the portable video projector 3102 mayproject and/or detect a control field. Optionally, the display field ofview may be monitored with a detector such as a scattered light detectorto enable feedback for use as a mouse, pointer, etc. as may be desiredby the user, such as for controlling the projected image.

As illustrated in FIG. 31, the portable scanned beam projection display3102 may includes a body having an output optical element 3104 mountedthereon according to an embodiment. According to some embodiments,output element 3104 may be rotated to a range of positions. For example,in a first position the optical element is shielded by the body of thedevice and the device is switched to an “off” or hibernate state. Theposition of the optical element 3104 may be sensed, for instance usingan optical encoder, a rotary switch, or the like to automatically switchmodes. In another exemplary position, the optical element 3104 may berotated to project an image generally forward at one or more anglesappropriate for intersecting a table surface. The projected image mayoptionally be automatically rotated such that “top” is positioned towardthe base of the body of the device 3102 for convenient viewing by a userfacing the front of the body. In a third exemplary position, the opticalelement 3104 may be rotated to a position generally forward and parallelwith the table surface, for example generally perpendicular to the longaxis of the body of the portable video projector 3102, to project animage on a wall while the body is positioned on a table. The positionmay be adjusted upward or downward from parallel with the table surfaceto select an image height on the wall. The projected image mayoptionally be automatically rotated to project an image whose “top” isoriented in an upward direction on the wall.

In a fourth position illustrated in FIG. 31, the optical element 3104 isrotated to a position generally parallel with the longitudinal axis ofthe body of the portable video projector 3102. In this mode, the imageprojector may be conveniently held in the hand of a user and pointedtoward a vertical or horizontal surface, such as while giving an ad hocpresentation.

As indicated above, the integrated photonics modules used in variousapplications may include image capture functionality. Images capturedmay be used to perform a variety of functions. For example it may bedesirable for an embodiment of the system 2901 of FIG. 29 to act as alaser camera in addition to providing a projection display.

The system 3001 of FIG. 30 may include analysis of captured video tosound an alarm, perform a system shutdown, convert to an “auto-pilot”,store a video or still image etc. depending upon a determinedcharacteristic of one or more vehicle occupants 3010. For example, if itis determined that the driver or pilot 3010 is in a near-sleep state, analarm may be used to awaken the individual. If it is determined that theoccupant is unknown and an alarm system has been disabled or otherwisetampered with, the system may capture an image of the occupant, shutdown the vehicle, and/or notify a law enforcement representative of thestate. If analysis of a series of video frames determines the occupantmay be under the influence, the system may notify the occupant to pullthe vehicle to the side of a road and subsequently perform at least apartial system shutdown until impairment is no longer an issue.

Similarly, the system 3001 may adjust display brightness, content, etc.dependent upon detected FOV or ambient lighting, etc.

As mentioned earlier, the system 3101 may act upon a captured image tocontrol the display content. Such action may be used, for example, to“pan” the display as a larger portion of a virtual image, correct fordisplay surface irregularities, compensate for relative motion betweenthe display surface and the portable video projector, etc.

The preceding overview of the invention, brief description of thedrawings, and detailed description describe exemplary embodimentsaccording to the present invention in a manner intended to foster easeof understanding by the reader. Other structures, methods, andequivalents may be within the scope of the invention. The scope of theinvention described herein shall be limited only by the claims.

1-16. (canceled)
 17. A beam scanner comprising: a selective reflectoraligned to receive a first beam of light along a first axis and reflectat least a portion of the first beam of light along a second axis; and aMEMS beam scanner aligned to receive the first beam of light along thesecond axis from the selective reflector and operable to reflect thefirst beam of light as a periodically scanned second beam of lighttoward a field of view substantially subtended by the selectivereflector; wherein the selective reflector is configured to allow asubstantial portion of the second beam of light to pass through to thefield of view.
 18. The beam scanner of claim 17 wherein: the selectivereflector includes a polarizing beam splitter; the first beam of lightis polarized in a direction the polarizing beam splitter is configuredto reflect; and the second beam of light is polarized in a direction thepolarizing beam splitter is configured to pass.
 19. The beam scanner ofclaim 18 further comprising: a polarization rotator aligned between thepolarizing beam splitter and the MEMS beam scanner.
 20. The beam scannerof claim 19 wherein the polarization rotator includes a quarter-waveretarder.
 21. The beam scanner of claim 17 further comprising an opticalframe operative to maintain alignment between the selective reflectorand the MEMS scanner.
 22. The beam scanner of claim B 14 furthercomprising at least one light source operable to emit a beam ofmodulated light coupled to the housing and held in alignment with theselective reflector and the MEMS scanner by the housing.
 23. The beamscanner of claim 21 further comprising: at least two light sourcesoperable to emit at least third and fourth beams of modulated light; anda beam combiner configured to combine the at least third and fourthbeams of modulated light into the first beam of light and launch thefirst beam of light along the first axis toward the selective reflector;and wherein the optical frame is operative to maintain alignment betweenthe at least two light sources, the beam combiner, the selectivereflector, and the MEMS scanner.
 24. The beam scanner of claim 16wherein the optical frame is further operative as a heat sink to removeheat from the at least two light sources.
 25. The beam scanner of claim16 wherein the at least two light sources include at least one diodelaser and at least one SHG laser.
 26. The beam scanner of claim 16wherein the at least two light sources include at least three lightsources, the at least three light sources comprising a red laser diode,a blue laser, and a green SHG laser.
 27. The beam scanner of claim 16further comprising a beam scanner controller operatively coupled to theat least two light sources and the MEMS scanner.
 28. The beam scanner ofclaim 20 wherein at least a portion of the beam scanner controller ismechanically coupled to the optical frame.
 29. The beam scannercontroller of claim 28 wherein substantially the entire beam scannercontroller is mechanically coupled to the optical frame.
 30. The beamscanner of claim 28 wherein the optical frame is further configured tobe physically mounted to a host system.
 31. The beam scanner of claim 20wherein the beam scanner controller includes a MEMS controller operableto drive the MEMS scanner.
 32. The beam scanner of claim 31 wherein thebeam scanner controller is further operable to generate and transmit ascanner synchronization signal.
 33. The beam scanner of claim 31 whereinthe beam scanner controller further includes at least one sensoroperable to measure an operating variable and transmit a signalcorresponding to the measured operating variable.
 34. The beam scannerof claim 33 wherein the operating variable includes at least oneselected from the list consisting of ambient light, temperature,automatic phase measurement, and scanner fault.
 35. The beam scanner ofclaim 31 wherein the beam scanner controller further includes lightsource drivers operable to receive a light source drive signal andresponsively drive the at least three lasers to emit modulated beams oflight.
 36. The beam scanner of claim 35 wherein the beam scannercontroller further includes a video controller operable to receive asynchronization signal from the MEMS controller and receive a videoimage and responsively transmit the light source drive signal to thelight source drivers synchronously with the synchronization signal. 37.The beam scanner of claim 36 wherein the video controller is operable toreceive the video image from a system resource.
 38. The beam scanner ofclaim 37 further comprising a media module operatively coupled to thesystem resource and the video controller and wherein the media module isoperable to receive a video image in a first format from the systemresource, convert the video image to a second format compatible with thevideo controller, and transmit the video image in the second format tothe video controller.
 39. The beam scanner of claim 23 wherein theoptical frame is further configured to be physically mounted to a hostsystem.
 40. The beam scanner of claim 17 wherein the second axis isaligned with a point substantially centered in the field of view. 41.The beam scanner of claim 17 wherein the MEMS beam scanner has a restposition and the second axis is aligned substantially normal to the restposition of the MEMS beam scanner.
 42. The beam scanner of claim 41wherein the rest position of the MEMS beam scanner corresponds to aposition taken by the mirror of the MEMS beam scanner when power isremoved from the MEMS beam scanner. 43-61. (canceled)